SEOUL, Jan. 23 (Yonhap) -- A frustrated North Korea hinted at conducting a nuclear test after the U.N. Security Council punished it with tightened sanctions for its December rocket launch, posing a major challenge to the incoming government of South Korean President-elect Park Geun-hye, analysts and diplomats said Wednesday.

The North's tough response came hours after the 15-nation council unanimously approved a new resolution that added more North Korean individuals and entities to a sanctions list and warned of "significant action" if it carries out another rocket launch or a nuclear test.

North Korea said in a statement carried by its official news agency that it "will take measures to boost and strengthen our defensive military power including nuclear deterrence."

While the resolution does not impose new sanctions against North Korea for its defiant Dec. 12 launch, Seoul diplomats said a vote from China, the North's last-remaining key ally, in favor of sanctions against Pyongyang was a blow to the regime of Kim Jong-un.

Despite the warning from the international community over a possible nuclear test, experts said North Korea has compelling political reasons to shrug it off as it traditionally tends to test new presidents in South Korea early in their term.

If so, it will present a major security crisis for the new government of Park, who is set to take office on Feb. 25.

"As North Korea strongly indicated the possibility of a nuclear test, the security situation on the Korean Peninsula is becoming more worrisome," said Hong Hyun-ik, an analyst at Sejong Institute, a Seoul-based think tank.

"If North Korea conducts a nuclear test, tensions will last for a long time," Hong said.

Park has pledged more engagement with North Korea than her predecessor, but made it clear that she won't reinstate major economic projects with the North unless Pyongyang abandons its missile and nuclear programs.

North Korea has been under U.N. sanctions since 2006 when it conducted its first nuclear test. The sanctions were tightened in 2009 after its second nuclear test.

A third nuclear test by North Korea would make it difficult for Park to lay out plans on how best approach the North, analysts said.

For the second-term administration of U.S. President Barack Obama, the North's nuclear test will force it to change its so-called "strategic patience" approach toward North Korea, a policy of shunning direct talks the North until it agrees to abide by past nuclear commitments.

"Strategic patience, strategic coma, whatever it is called, has allowed North Korea to patiently develop nuclear and missile programs," said Victor Cha, who was a top adviser on the Koreas to former U.S. president George W. Bush.

Cha told a Seoul forum on Tuesday that the U.S. policy "has not been working and we need to do something else."

Seoul diplomats hope China, which keeps North Korea's moribund economy afloat, will exert more influence on the North to try to get it to change its policy of confrontation.

The new U.N. resolution raised some hope.

"The tone of the words used in the resolution was a result of negotiations between the U.S. and China," Kim Sook, South Korea's ambassador to the U.S., told reporters in New York.

"The U.S. had insisted that it won't negotiate with China over the content of the resolution unless there is an agreement to adopt the resolution," Kim said. "In this regard, China accepted the U.S. stance."